Meeting Abstract

P1.9  Sunday, Jan. 4  The implications of body size for habitat selection as a consequence of behavioral thermoregulation SMITH, Jeffrey J.*; SEARS, Michael W.; Southern Illinois University eutrophy@gmail.com

Body size is an important factor determining the range of body temperatures available to an ectotherm on a daily basis. Typically, small- and medium-sized vertebrate ectotherms (< 1 kg) can potentially experience body temperatures that range over a span of 30 C. To optimize physiological performance, individuals can use behavioral thermoregulation to minimize this variance by differentially selecting microhabitats in an environment. The ecological implications of this behavior is that animals that differ in size will likely occupy different parts of the environment to maintain similar body temperatures all else being equal, and that time for activity will differ for individuals of different sizes across microhabitats. Here, we use a simulation to explore the implications of thermoregulation for daily and seasonal activity for differently sized reptiles in a spatially-explicit, thermally-heterogeneous landscape. Several patterns emerge from these simulations. With respect to time, relatively small individuals can take advantage of microhabitats for heating at earlier times of day than larger individuals. Further, the activity of relatively small individuals is depressed during the hottest times of day and year. With respect to space, smaller individuals cannot penetrate as deeply into cooler (shaded) habitat as can larger individuals. Implications are that these shifts in spatiotemporal patterns of activity might be able to relieve intraspecific or interspecific competition among individuals that coexist in space.